Grinding machine



J. l. GARSIDE GRINDING MACHINE Nov. 36, 1948.

4 Sheets-Sheet 1 Filed Sept. 7. 1945 CR8 I05 CRV CR Swan/who; JOHN 1. G ARSlDE J. I. GARSIDE GRINDING MACHINE Nb v. 30, 1948.

4 Sheets-Sheet 2 Filed Sept. 7, 1945 Ill JOHN l. G Aaswa J. l. GARSIDE GRINDING MACHINE Nov. 30,1948.-

4 Sheets-Sheet 3 Filed Sept. 7, 1945 woe/14M JOHN I, qARslDE w Kw u vw .f Q 9 W Patented Nov. 30, i

GRKNDING MAG at E John E. Garside, West Boylston, Mesa, assignor to Norton Company, Worcester, Mata, a corporation of Massachusetts Application September 7, 1945, Serial No. 614,912

\ 13 Claims.

The invention relates to grinding machines, and more particularly to a machine for auto matically and successively grinding a plurality of work pieces.

One object of the invention is to provide a simple and thoroughly practical hydraulically operated, electrically controlled automatic grinding machine for automatically grinding a plurality of work pieces. Another object of the invention is to provide .an automatic grinding machine in which work pieces are loaded on a work turret and successively fed into an operative position and ground to thedesired and predetermined extent. Another obiect of the invention is to provide an automatic grinding machine for grinding a predetermined surface on' the end of a work piece. Another object of the invention is to provide an automatic grinding machine for successively grinding predetermined slots in the end of connecting rods and the like. Other objects will be in part obvious or in part pointed out hereinafter.

The invention accordingly consists in the features of construction, combinations of elements, and arrangements of parts, as will be exemplified in the structure to be hereinafter described, and the scope of the application of which will be indicated in the following claims.

In the accompanying drawings in which is shown one of various possible embodiments of the mechanical features of this invention,

Fig. 1 is a front elevation of the improved automatic grinding machine;

Fig. 2 is a combined hydraulic piping diagram and electrical wiring diagram of the control mechanisms of the machine;

Fig. 3 is a fragmentary right-hand end elevation, on an enlarged scale, ofthe work loading turret;

Fig. 4 is a fragmentary vertical sectional view, taken approximately on the line $4 of Fig. 3, of the rotatable support for the work loading turret;

Fig. 5 is a left-hand end elevation, on an enlarged scale, partly in section, of the work turret indexing mechanism; 7

Fig. 6 is a fragmentary sectional view, on an enlarged scale, of one of the spring clips and pins for locating and holding a work piece on the work loading turret; and

Fig. 7 is a fragmentary sectional view, on an enlarged scale, through the hydraulic mechanism for clamping a work piece when in an operative position on the work loading turret.

A grinding machine has been illustrated in the drawings comprising a base In which supports a A transversely movable wheel slide it is ar--- ranged to slide transversely relative to the base It on the usual V-way and flat way (not shown). The wheel slide It supports a rotatable'grlncling wheel it at one end of a wheel spindle (not shown). The .wheel it is preferably driven by an electric motor it mounted on the upper surface of the wheel slide it. The motor is provided with an armature shaft 16 having a driving pulley il mounted thereon. The driving pulley ii is connected by a driving belt it with a pulley 89 mounted on the right hand end of the wheel spindle.

In order to facilitate positioning the table it so as to position the work pieces to be ground relative to the grinding wheel it, a suitable manually operable traverse mechanism is provided comprising a manually operable traverse wheel 20. The traverse wheel 20 is rotatably mounted on a shaft 22 which is connected by means of a gear (not shown) with a gear 22 which is mounted on a shaft 23. The shaft 23 also supports a gear M which meshes with a rack bar 25 depending from the under side of the table II. It will be readily apparent from the foregoing disclosure that a rotary motion of the hand wheel 20 will be transmitted through the mechanism above described to move the table it longitudinally in either direction. The direction of movement of the table it depends upon the direction of rotation of the hand wheel 20.

A suitable feeding mechanism is provided for manually adjusting the position of the wheel slide it and grinding wheel It comprising an old and well known feed wheel 28 having a micrometer adjusting mechanism 21. The feed wheel 26 is operatively connected to rotate a gear 28 which is mounted on the end of the feed screw shaft 29. The feed screw shaft 29 is operatively connected to rotate a feed screw (not shown) which meshes with a half nut (not shown) depending from the under side of the wheel slide ll. This feed mechanism is substantially the same as that shown in the prior U. 8. Patent to Carl G. Flygare et al., No. 2,349,786, dated May 23, 1944, to which reference may be had for details of disclosure not illustrated and contained herein.

In order to facilitate a power traverse or reciprocation of the table II for a traverse grinding operation, a hydraulically operated mechanism is provided comprising a cylinder 3|) which is fixedly supported on the under side of the table H. The cylinder 38 contains a pair of spaced pistons (not shown) which areconnected by hollow piston rods 33 and 34 respectively with hollow end brackets 38 and 36 respectively which are mounted on opposite ends of the base [8. This hydraulic table drive mechanism is substantially the same as that shown in the prior U. 8. Patent to Wallace H. Wood, No. 2,071,677, dated February 23, 1937, to which reference may be had for details of disclosure not contained herein.

A pair of pipes 31 and 38 connect the brackets 38 and 35 respectively with a control valve unit 38. The control valve unit 38 comprises a reversing valve for controlling the direction of flow of fluid to and from the cylinder 38 and also contains a combined start and stop valve and speed control valve for regulating the exhaust of fluid from the cylinder 38 so as to control the speed of movement of the table II. The control valve unit 38 is identical with that disclosed in prior U. S. patent to W. H. Wood above referred to.

A hydraulic system is provided for supplying fluid under pressure to reciprocate the table comprising a fluid reservoir 48 formed within the base ID. A motor driven fluid pressure pump 4| draws fluid through a pipe 42 from the reservoir 40 and passes fluid under pressure through a pipe 43 to the control valve 39. An adjustable relief valve 44 is connected in the pipe line 43 by means of which excess fluid under pressure may be returned directly to the reservoir 48, thus facilitating maintaining a predetermined operating pressure within the hydraulic system.

A manually operable start and stop lever 45 is provided for actuating the stop and start valve so as to start and stop the movement of the table H as desired. A pivotally mounted reversing lever 46 is mounted on the front of the machine base and is operatively connected to actuate the.

table reversing valve in timed relation with the reciprocatory movement of the table ii. A pair of adjustable table dogs 41 and 48 are adiustably supported in a T-slot 49 formed in the front edge of the table II. It will be readily apparent that the positioningof the dogs 41 and 48 determines the length of the reciprocatory stroke of the table H. This table traversing and reciprocating mechanism is identical with that shown in the above referred to prior patent to Wood, to which reference may be had for details of disclosure not contained herein.

In order to support a plurality of work pieces so that they may be intermittently and successivelypositioned for a grinding operation, the work support I! is provided with a rotatable work loading turret 50 (Figs. 1, 3 and 4). The work turret 58 is mounted on one end of a rotatable shaft 51 which is journalled in anti-friction bearings 52 and 53 supported within the work supporting head l2. As illustrated in the drawings, the machine as set up is particularly adapted for grinding a predetermined slot in the end of a connecting rod. To facilitate locating a pinrality of work pieces 54 on the turret 58, a pin-- rallty of locating pins 55 are fixedly mounted on the work loading turret 58. These locating pins 55 are of a predetermined diameter to mate with a finished hole 58 formed in the ends of the connecting rod 54. A plurality of locating studs 51 are provided on the work loading turret 88 which cooperate with a plurality of spring clips 58. It will be readily apparent from the foregoing disclosure that a connecting rod 84 may be slid manually into an operative position with the hole 88 of the connecting rod 84 mating with one of the studs 55 on the work turret 88 and the main part of the connecting rod being held against one of the pins 81 by means of one of the spring clips 58.

The work loading turret 58 is preferably arranged so that it may be automatically indexed successively to present work pieces into a grinding relationship with the grinding wheel M. This mechanism preferably comprises an automatically actuated indexing mechanism comprising an index plate 88 which is fixedly mounted on a reduced left-hand end portion of the turret shaft 5|. An actuating pawl BI is provided for intermittently indexing the plate 88 to index the turret wheel 50 as desired. 4

A holding pawl 83 is pivotally supported on a stud 84 which is in turn supported on a bracket which is formed integral with or fixedly mounted on the head I2. The holding pawl 63 is provided with a shaped end which is arranged to mate under the influence of gravity with one of a plurality of notches 88 formed in the periphery of the index plate 88.

The indexing pawl 8| is supported at one end of a pivotally mounted arm 81. The arm 61 is pivoted on a stud 68 which is carried by a rock plate 1 I. The rocking member 1| is pivotally supported on the reduced cylindrical portion of the shaft 5|. A stop pin 18 is provided on the plate H to limit the swinging movement of the pawl arm 61 in a counterclockwise direction (Fig. 5). A pair of adjustably mountedstop screws 12 and 13 are provided to limit the rocking movement of the member 1i in either direction.

In order that the index pawl 8i may be automatically actuated in timed relation with the other mechanisms of the machine, a hydraulically operated mechanism is provided comprising a fluid pressure cylinder 88 which contains a slidably mounted piston 81. The piston 8l is fixedly connected to one end of a piston rod 82. The piston rod 82 is connected by means of a pivot stud 83 with a pivotally mounted arm 84 which is in turn connected by a stud 85 with the pawl carrying arm 61. A compression spring 86 surrounds the piston rod 82 and is interposed between the cylinder head at the left-hand end of the cylinder 88 and the piston 8| (Fig. 5). The compression of the spring 88 serves to move the piston 8| toward the right (Fig. 5) which serves to move the pawl arm 81 in a counterclockwise direction to withdraw the index pawl 8i from the notch 86 until arm 51 engages stop pin 18 after which plate H is rocked in a counterclockwise direction (Fig. 5) through an idle stroke into dotted line position.

The index pawl arm 61 is provided with an upwardly extending arm 86 having a cam face 81 formed adjacent to its upper end. When the index pawl Si is moved through an idle or inoperative stroke, the arm 86 moves upwardly into dotted line position 880. with the cam face 81 in position 81a.

When it is desired to effect an indexing movement of the work turret I58, fluid under pressure is admitted through a pipe 88 into a cylinder chamber 88 formed at the right-hand end of the cylinder 88 to cause the piston 8i to move from the dotted line position 81a (Fig. 5) into full line position. During the initial part of the piston stroke, the index pawl arm 81 will be rocked in a clockwise direction on the pivot stud 88 so that the index pawl 8! will engage the next notch 68 on the index plate 88. At the same time, the arm determined extent.

assopo'a cam face 01 moves from position 01a into position- 'Ib. During this movement of the cam 01, the cam face engages a hub portion 00 formed on the holding pawl member 00 and rocks the holding pawl 03 in a clockwise direction out of engagement with the notch 88, after which continued movement of the piston 0| toward the left turns the index plate 60 in a clockwise direction (Fig. 5) to index the next work piece 00 into an operative grinding position. The holding pawl 00 then drops into the next notch 00 to locate the work loading turret 00 with the next work piece 00 in an operative position for grinding a predetermined slot 0i in the end portion thereof.

A Suitable clamping mechanism is provided to hold a work piece 00 rigidly in position on the work loading turret during a grinding operation.

This mechanism may comprise a hydraulic cylinder 00 having a piston 00 slidably mounted therein. A piston rod 0? is fixedly connected at one end to a piston 00. The other end of the piston rod 0? is arranged to engage a hub portion 00 of the work piece 06' when fluid under pressure is admitted through a pipe IIO into a cylinder chamber 00 rigidly to clamp the work piece 00 on the work loading turret 00. A compression spring 00 surrounds the piston rod ill and is interposed between the piston 00 and'the cylinder head enclosing the left-hand end of the cylinder 90. The released compression of the spring 00 serves to move the piston 00 toward the right (Fig. 7) when fluid is allowed toexhaust from the chamber 00 to unclamp a work piece 00.

A hydraulically operated wheel feeding mechanism is provided rapidly to move the grinding 6 .In the position of the control valve I 00, fluid under pressure in the pipe I00 passes through a pipe I I0 into a cylinder chamber II I tomove the piston IOI (upwardly as shown in Fig. 2) .Iso as to move the grinding wheel is and the wheel slide I0 each rearwardly into an inoperative position. During this movement, fluid within a cylinder chamber H2 exhausts through a pipe H0, through the valve I 05 and out through an exhaust pipe I it into the reservoir 00. When the solenoid I00 is energized the control valve I00 is shifted into a reverse position so that fluid under pressure from the pipe I00 passes through a pipe H0 into a cylinder chamber M2 to cause a forward movement of the piston IOI the wheel slide it and the grinding wheel It to grind the work piece 00 to the desired and predetermined extent. .During the forward feeding movement of the piston IOI, fluid within the cylinder chamber III exhausts through the pipe IIO through the valve I00 and out through an exhaust pipe i I0 into the reservoir 00.

In the position of the valve I00, as shown in I Fig. 2, fluid under pressure passing through the wheel it into operative engagement with the work piece 00 to be ground and then slower to grind the work piece 00 to the desired and preprise a hydraulic cylinder I00 which is fixedly mounted relative to the base I0 of the machine. The cylinder I00 contains a slidably mounted piston I0i which is fixedly connected to a double end piston rod I 02. The piston rod I02 is preferably arranged in axial alignment with the feed screw (not shown). This feeding mechanism is substantially the same as that shown in the prior U. B. Patent No. 2,349,786, to Carl G. Flygare et al., dated May 23, 1944, to which reference may be had for details of disclosure not contained herein. In addition to the cylinder I00 and piston IOI, this mechanism may, if desired, also include a dash pot feed regulator such as that disclosed in the prior patent aibove referred to. This mechanism is not considered a part of the present invention and consequently has not been illustrated in detail.

A fluid pressure system if provided for supplying fluid under pressure to the cylinders 00, 00 and I00. This fluid system may comprise a motor driven fluid pump I03 ({F'ig. 2) which is arranged to supply fluid under pressure through a pipe I00 to a control valve I00 which controls the admission to and exhaust of fluid from the feed cylinder I00. The control valve I05 is preferably electrically controlled by means of a solenoid I08. The pump I03 also forces'fluid under pres-' sure through a pipe I01 to a control valve I08. The control valve I08 is arranged to control the admission to and exhaust of fluid from the cylinders 00 and 05. The control valve I08 is preferably electrically controlled by means of an electric solenoid I00.

This mechanism may come.

pipe I01 passes through the valve I00, through a pipe H5 into a cylinder chamber I50 in the cylinder 00 to move the piston all so as to impart an indexing movement to the index pawl 0i.

In this position of the valve I00, fluid in a cylinder chamber III in the cylinder 05 may exhaust through a pipe M0, through the control valve I00 and through an exhaust pipe H9 into the reser-- voir 00. When the solenoid I00 is energized, the valve I00 is shifted into a reverse position so that fluid under pressure in the pipe I0'I will pass through the valve I00, through the pipe IIO into the cylinder chamber 00 to move the piston 00 toward the left (Fig. 2) so as to clamp the work piece 00 in an operative grinding-position on-the work loading turret 50 during the next'grinding operation. With the valve in this position, the released compression of the spring 00 moves the piston 0i so as to exhaust fluid'from the cylinder chamber H6 through the pipe II5, through the valve I00 and out through an exhaust pipe I20 into the reservoir 00. This latter movement of the piston 8i serves to move the index pawl 6! through an idle stroke so that it is' ready for the next indexing operation.

In order to obtain one of the main objects of this inventionpit is desirable to provide an automatic control mechanism whereby successive work pieces 00' may be automatically ground to the desired and predetermined extent without stopping the machine. To facilitate provisions of an automatic control cycle, an electrical control system is provided for controlling the solenoid actuated valves I05 and I08. This electrical control mechanism may comprise a start switch I25 and a stop switch I26 which are arranged to be actuated by a manually operable control lever I21. The control lever I21 is pivotally supported on the front of the machine base ID. This electrical control apparatus has been illustrated diagrammatically in Fig. 2 including power lines LI and L2 which supply the source of electrical power for operating the machine. Electrically operated relay switches CR, CR8 and CRV are provided for controlling the cycle of operation. A normally closed limit switch LSI is held open when the piston rod I02 is in a rearward position. A normally closed limit switch LS2 is arranged to be openedduring the forward or infeeding movement of the grinding wheel. A normally open limit switch, LS3 is arranged to be closed by the disclosure.

piston rod 82 when it is moved toward the left (Fig. 55 to index the work loading turret 00. To start a grinding cycle, it is merely necessary to manually shift the control lever I21 in a counterclockwise direction- (Fig. 2) to close the starta circuit and immediately terminate the grinding cycle and return the grinding wheel and the wheel slide I3 to a rearward or inoperative position.

The operation of this improved grinding machine will be readily apparent from the foregoing Assuming all adjustments to have been previously made. when it is desired to start a grinding operation a plurality of work pieces 54 are manually loaded on to a work loading turret 50 in a manner above described. The cycle control lever I21 is then rocked in a counterclockwise direction (Fig. 2) to close the cycle startswitch I20. Closing of the switch I25 serves to energize the relay switch CR which closes a circuit to energize the relay switch CBS. The energizing of relay switch CBS closes a circuit to energize the solenoid I08 to shift the feed control valve I into a reverse position so that fluid under pressure will be passed from the pipe I04, through the pipe H3 into the cylinder chamber II2, to start a forward feeding movement of the wheel slide i3 and the grinding wheel I4. During the initial forward movement of the. piston IIII. the limit switch LSI is closed which closes a circuit to energize the relay switch CRV. Energizlng of the relay switch CRV serves to close a circuit to energize the solenoid I09 and thereby to shift the valve I08 so as to admit fluid under pressure through the pipe H8 into the cylinder chamber 99 so as to clamp a work piece 54 in an operative grinding position on the work loading turret 50-. The shifting of the valve I08 into this position serves to allow fluid to exhaust from the cylinder chamber H6, through the pipe H5, through the valve I08, and out through the exhaust pipe I20 into the reservoir 40. The exhausting oi fluid from the cylinder chamber H8, as facilitated by the release compression of a spring 86, returns the piston 8| into position 8Ia (Fig. 5). to withdraw the index pawl BI through an idle stroke during which the limit switch LS3 opens. During the idle stroke of the indexing pawl BI, the index plate 60 is held against rotary motion by means of the holding pawl 63.

The forward feeding movement of the grinding wheel It continues to grind a slot of a predetermined width to a predetermined depth in an end of a work piece 54. When the grinding wheel I4 has reached the desired forward position and g the work has been ground to the desired predetermined extent, the limit switch LS2 opens to open a circuit thereby de-energizing the relay switch CRS which in turn dc-energizes the solenold I06 and allows the valve I05 to shift into the position illustrated in Fig; 2. In this position of the valve I05 fluid under pressure is passed from the pipe I04, through the valve I05, through the pipe IIO into the cylinder chamber III to move the piston IOI together with the grinding wheel This movement of the piston BI serves I4 and the wheel slide it rearwardly to an inoperative position. When the grinding wheel it approaches its rearward or inoperative position the limit switch LSI opens to de-energize the relay switch CRV so as to de-energize the solenoid I08 and thereby to shift the valve I08 into the position illustrated in Fig. 2. In this position of the valve I08, fluid is exhausted from the cylinder chamber 89 of the work clamp cylinder 85. under the influence of the released compression of the spring 84, through the pipe IIB. through the valve I08 and out through the exhaust pipe I I9 into the reservoir 40. The released compression oithe spring 95 moves the piston 88 toward the right (Figs. 2 and 'I) to unclamp the work piece 04. At the same time the valve I08'is shifted into the position illustrated in Fig. 2, fluid under pressure from the pipe I01 is passed through the valve I08, through the pipe III into the cylinder chamber IIB to move the piston 8| to shift the index pawl BI through the operative indexing stroke. The index pawl 8i rocks into engagement with the next notch 88 in the index plate 60 and then turns the index plate so as to index the work loading turret 00 to shift the next work piece 54 into an operative grinding position ready for the next grinding operation. At

the same time the turret 50 indexes, the ground piece of work 0 is shifted out of a grinding position so that it may be readily unloaded manually by the operator. I

The indexing movement of the piston 0i serves to close the limit switch LS3. The limit switch LS2 has previouslybeen closed by movement of the grinding wheel I4 to an inoperative position so that the closing of the limit switch LS3 serves to energize the relay switch CRS to thereby start the next grinding cycle. This cycle of operation will continue indefinitely to repeat itself until interrupted by manual movement of the control lever 21. If at any time during a grinding cycle it is necessary and desirable to interrupt and stop the grinding operation, the control lever I21 may be rocked in a clockwise direction (Fig. 2) to open the stop switch I28, thereby breaking a circuit to de-energize the relay switch CR which operates automatically to break a circuit and thereby to turn the grinding wheel I I immediately to a rearward or inoperative position.

It will thus be seen that there has been provided by this invention apparatus in which the various objects hereinabove set forth together with many thoroughly practical advantages are successfully achieved. As many possible embodiments may be made of the above invention and as many changes might be made in the embodiment above set forth, it is to be understood that all matter hereinbefore set forth orshown in the accompanying drawings is to be interpreted as illustrative and not in a limiting sense.

I claim: I

1. In a grinding machine having a transversely movable slide, means rotatably to support a grinding wheel on said slide, means including a piston and cylinder automatically to feed said slide transversely toward and from a work piece 2. In a grinding machine having a transversely movable slide, means rotatably to support a grindin wheel thereon, means including a piston and cylinder to feed said grinding wheel slide transversely toward and from a work piece, a

work supportincluding a rotatable work supporting turret to support a plurality of work piston and cylinder actuated pawl to index said,

turret successively to present work pieces into an operative position. r

3. In a grinding machine having a transversely movable slide, means rotatably to support a grinding wheel thereon, means including a piston and cylinder to feed said grinding wheel slide transversely toward and from a work piece, a solenoid actuated control valve therefor, a work support including a rotatable work supporting turret to support a plurality of work pieces, a hydraulically operated means including a piston and cylinder to clamp a work piece on said turret during a grinding operation, an'index mechanism including a piston and cylinder actuated pawl to index said turret successively to present work pieces into an operative position, and a solenoid actuated control valve to control the admission to and exhaust of fluid from said work clamping and said turret indexing cylinders.

a. In a grinding machine having a transversely movable slide, means rotatably to support a grinding wheel thereon, means including a piston and cylinder to feed said grinding wheel slide transversely toward and from a work piece, a solenoid actuated control valve therefor, a work support including a rotatable work supporting turret to support a plurality of work pieces, a hydraulically operated means including a piston and cylinder to clamp a work piece on said turret during a grinding operation. an index mechanism including a piston and cylinder actuated pawl to index said turret successively to present work pieces into an operative position, a solenoid actuated control valve to control the admission to and exhaust of fluid from said work clamping and said turret indexing cylinders, and means including a limit switch actuated by rearward movement of the wheel slide to energize the first solenoid valve so as to start a grinding cycle.

5. In a grinding machine having a transversely movable slide, means rotatably to support a grinding wheel thereon, means including a piston and cylinder to feed said slide transversely toward and from a work piece, a work support in cluding a rotatable work supporting turret to support a plurality of work pieces, hydraulically operated means including a piston and cylinder to clamp a work piece on said turret during a grinding operation, an index mechanism to index successively work pieces into operative positions including a pawl and ratchet means, a spring to iii ill

means including a piston and cylinder to feed.

said slide transversely in either direction, a work support including a rotatable work supporting turret successively to convey a plurality of work pieces to and from an operative position, means on said turret precisely to locate a plurality of work pieces thereon, an indexing mechanism including a pawl and ratchet to index said turret, a spring actuated means to move said pawl through its idle stroke, and a piston and cylinder to actuate said pawl through an operative stroke.

7. In a grinding machine having a base, a transversely movable slide thereon, means r0- tatably to support a grinding wheel on said slide,

.means to feed said slide in either direction, a

work support including a rotatable turret successively to convey a plurality of work pieces to a and from an operative position, a plurality of locating and supporting devices on said turret precisely to locate a plurality of work pieces in substantially radial position on said turret, an

indexingmechanism including a pawl and ratchet to index said turret, a piston and cylinder to actuate the pawl through an indexing stroke,

means including a solenoid valve to control the flow of fluid to and from said cylinder means including a limit switch actuated in timed relation with the movement of-the wheel slide toward an.

inoperative position to initiate the next grinding cycle, and means including a limit switch which is actuated by said wheel slide during its rearward movement to actuate said solenoid valve and thereby to index said turret.

8. In a grinding machine as claimed in claim 3 in combination with the parts and features therein specified of means including a starter switch to energize the wheel feed solenoid valve to initiate an infeeding movement of the grinding wheel, means including a limit switch actuated by the infeeding of the grinding wheel to actuate a second solenoid valve to admit fluid under pressure to the work clamping cylinder so as to clamp a work piece in an operative position on said turret during a grinding operation, a second limit I switch which is actuated when the grinding wheel approaches its forward position to actuate the wheel feed solenoid valve so as to cause the grinding wheel to move rearwardly to a nonoperative position, said rearward movement of the grinding wheel serves to actuate said first limit switch to actuate the second solenoid valve so as to unclamp the ground work piece and thereafter to index the work turret to present the next work piece in an operative grinding position.

9. In a grinding machine as claimed in claim 3 in combination with the parts and features therein specified of means including a starter switch to energize the wheel feed solenoid valve to initiate an inieeding movement of the grinding wheel, means including a limit switch closed by the infeeding of the grinding wheel to energize a second solenoid valve to admit fluid underpressure to the work clamping cylinder so as to clamp a work piece in an operative position on said turret during a grinding operation, a second limit switch which is opened when the grinding wheel approaches its forward'position to de-energize the wheel feed solenoid valve so as to cause the grinding wheel to move rearwardly to a nonoperative position, said rearward movement of the grinding wheel serves to open said first limit switch to de-energize the second solenoid valve so as to unclamp the ground work piece and thereafter to index the work turret to present the next work piece in an operative grinding position.

10. In a grinding machine as claimed in claim 3 in combination with the parts and features therein specified of means including a starter switch to actuate the wheel feed solenoid valve to initiate an infeeding movement of the wheel slide, means including a limit switch which is actuated by the infeeding movement of said slide to actuate a second solenoid valve so as to admit fluid under pressure to said work clamp cylinder to clamp a work piece in an operative position on said turret during a grinding operation, and a second limit switch which is actuated by said slide when the slide reaches its forward position to actuate the wheehfeed solenoid valve so as to cause a rearward movement of the wheel slide to an inoperative position, the rearward movement of the wheel slide actuates said first limit switch to actuate the second solenoid valve to allow fluid to exhaust from the work clamp cylinder so as to unclamp the ground work piece and to admit fluid under pressure to the index cylinder so as to index the work turret to present the next work piece in an operative grinding position.

11. In a grinding machine as claimed in claim 3 in combination with the parts and features therein specified of means including a starter switch to energize the wheel feed solenoid valve to initiate an infeeding movement of the wheel slide, means including a limit switch which is closed by the infeeding movement of said slide to energize a second solenoid valve so as to admit fluid under pressure to said work clamp cylinder to clamp a work piece in an operative position on said turret during a grinding operation, and a second limit switch which is opened by said slide when the slide reaches its forward position to de-energize the wheel feed solenoid valve so as to cause a rearward movement of the wheel slide to an inoperative position, the rearward movement of the wheel slide opens said first limit switch to de-energize the second solenoid valve to allow fluid to exhaust from the work clamp cylinder so as to unclamp the ground work piece and to admit fluid under pressure to the index cylinder so as to index the work turret to present the next work piece in an operative grinding position.

12. In a grinding machine as claimed in claim 3 in combination with the: parts and features therein specified of means including a starter switch to actuate the wheel feed solenoid valve to initiate an inieeding movement of the grinding wheel, means including a limit switch which is actuated by the infeeding movement of said slide to actuate a second solenoid valve so as to admit fluid under pressure to said work clamp cylinder to clamp a work piece in an operative position onsaid turret during a grinding operation,

a second limit switch which is actuated by said slide when the slide reaches its forward position to actuate the wheel feed solenoid valve so as to cause a rearward movement of the wheel slide to an inoperative position, the rearward movement of the wheel slide actuates said first limit switch to actuate the second solenoid valve to allow fluid to exhaust from the work clamp cylinder so as to unclamp the ground work piece and thereafter to admit fluid under pressure'to the index cylinder so as to index the work turret to present the next work piece in an operative grinding position, said rearward movement of the wheel slide serves to actuate the second limit switch to again actuate the wheel feed solenoid valve automatically to initiate the next grinding cycle.

13. In a grinding machine as claimed in claim 3 in combination with the parts and features therein specified of means including a starter switch to energize the wheel feed solenoid valve to initiate an infeeding movement of the grinding wheel, means including a limit switch which is closed by the infeeding movement of said slide to energize asecond solenoid valve so as to admit fluid under pressure to said work clamp cylinder to clamp a work piece in an. operative position on said turret during a grinding operation, a second limit switch which is opened by said slide when the slide reaches its forward position to derenergize the wheel feed solenoid valve so as to cause a rearward movement of the wheel slide to an inoperative position, the rearward movement of the wheel slide opens said first limit switch to de-energize the second solenoid valve to allow fluid to exhaust from the work clamp cylinder so as to unclamp the ground work piece and thereafter to admit fluid under pressure to the index cylinder so as to index the work turret to present the next work piece in an operative grinding position, said rearward movement of the wheel slide serves to close the second limit switch to again energize the wheel feed solenoid valve automatically to initiate the next grindingcycle.

JOHN I. GARSIDE.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,017,881 Landis Feb. 20, 1912 1,837,319 Fraser. Dec. 22, 1931 1,891,657 Theler Dec. 20, 1932 1,989,517 Holmes Jan. 29, 1935 2,003,269 Arter et al May 28, 1935 2,229,312 Silven et al Jan. 21, 1941 2,270,590 a Johnson Jan. 20, 1942 

